Home	Strange Wonderful Things Rare and exotic plants & seeds

Tree Dahlia

Dahlia imperialis

Please plant your cuttings as soon as you receive them.

  Start with a well-draining soil mix, such as 1 part potting soil to 1 part perlite, pumice or coarse horticultural sand.   Use a container about 1 gallon (4) in size, with drainage holes. 

  Plant the branch vertically about half-way in the soil so that at least one of the nodes is under the soil.  I have marked the cuttings so that you know which end goes "down".  Do not plant them upside down!

 If you have a rooting hormone like Rootone, or a fungicide, dust the branch with it first, although this is not necessary.  Wear a mask to avoid breathing the dust.

 After planting them, don't pack the soil down, and do not fertilize if your soil already contains fertilizer (check the label).  Water the soil so that it's lightly moist throughout, but not soggy. 

 Put the pots in a spot that is bright but without direct sun, and about 65-75 degrees F (18-24°C) day and night.

 The cuttings should begin sending out roots within 1 to 2 months.  Note: Cuttings often send out new growth before they have actually rooted, so do not give any direct sun until it has at least 8 inches (20 cm) of new growth and the branch is solidly rooted when you tug on it.  Once it is well-rooted, start giving it either filtered sun, or 2-3 hours of morning or late afternoon sun.  Increase the sun a little at a time until it is in 1/2 to full sun by the time it is 3 feet (1 meter) tall.

Fertilizer -- About every 2 months, give your plants a slow-release fertilizer such as pelleted fertilizer.

 It's normal for an older leaf to occasionally turn yellow and drop, but if it seems excessive, the plant may need more nitrogen fertilizer, or the soil may be too dry.

Planting out -- Once the plant is 3 feet (1 meter) tall, it may be planted in the ground.  If you keep it in a pot, use as large a pot as possible.  In hotter climates, try to shade the pot to keep the roots cool, and avoid using a black pot.

Climate -- Tree Dahlia will flower in Zones 8 to 10, although it's known to flower in Zone 7b in warmer years.  Temperatures below freezing may kill the flower stems, which appear around November or December.  The dormant tubers are said to be hardy to 20-25 degrees F (-7 to -4°C) if planted deep and well-mulched.  Or just move the tubers indoors for the winter.  Protection from strong winds is recommended, as the new shoots and flower sprays are fairly delicate. Either full sun or a half-day of sun is fine.

Watering -- Mature plants grown in the ground can be fairly drought-tolerant, but for the first couple of years, aim to keep the soil evenly moist most of the time.   

Pruning -- If for some reason you don't want a giant-sized plant, you may keep it to a reasonable height by pruning the tops one or more times throughout the season.  Cutting the tips will make the plant bushier.  After flowering, the plants naturally drop most or all of their branches.

Bugs to watch for -- Spider mites, aphids, leaf-miners, snails/slugs.

 By the way, if the cuttings are take a long time to root, scratch the stem with your fingernail to see if it's green inside, which means it's still alive.

Have fun growing them!

Jeff

Strange Wonderful Things

 

Home	Strange Wonderful Things Rare and exotic plants & seeds
Entire site Copyright 2004-2012 by Strange Wonderful Things, except as noted